Solar energy heater with heat pipe and heat exchanger

ABSTRACT

A solar energy heat exchanger includes a heat pipe that directly heats flowing water in a supplied pipe. A solar collector plate collects solar energy in one part of the heat exchanger. A portion of the heat pipe is located in the solar collector plate. A second part of the heat pipe transfers heat to water in the supply pipe. A heating system is also described. The heating system includes a solar energy heat exchanger, a hot water reservoir, and a heater to distribute heat to a building. Optional supplemental energy sources and control units to regulate operation may also be used. The heat pipe in the heat exchanger may contain capillary tubes to circulate thermally conductive media within a closed heating manifold.

FIELD OF THE INVENTION

[0001] The present invention relates to a heat exchanger and heating apparatus for use in connection with a solar energy collector.

BACKGROUND OF THE INVENTION

[0002] The heat exchanger comprises a heat pipe to directly contact a water supply pipe, exchange heat with the flowing water, and provide the heated water for use elsewhere, such as for example, in a heating system for a building, or a hot water supply for other uses.

[0003] To In conventional heating apparatuses using solar energy, such conventional systems consist of a heat collection component, a heat condensing unit, and a heater. Conventional units are typically classified according to the method of heat transfer carried out from one unit to another. By way of example, conventional solar energy powered heating apparatuses may be classified as active systems, passive systems, or hybrid systems. Among these conventional systems, the active system is most commonly used by consumers. An active system typically includes a solar energy collector, a heat exchanger which transfers and exchanges heat from a collection plate to a heat condensing tank, and a pump. For effective transfer of heat in conventional systems, anti freeze additives, such as for example, ethylene glycol, are diluted with water and are used as thermally conductive fluid media. Solar energy is transferred to a collection plate and in turn heat is stored in the form of hot water within a heat condensing tank. The size of the heat condensing tank typically offers a hot water supply capable of lasting between about 1 to 3 days without further intake or supply of additional solar energy. Some of the heat energy stored in the heat condensing tank is used for bathing. Heat stored in the heat condensing tank is transferred to an absorption type refrigerator during summer months. During cold temperature seasons, the stored heat in the heat condensing tank is transferred to a hot coil unit used to heat a room or other portion of a building. In conventional systems, an absorption type refrigerator is powered by heat energy supplied during the summer months. However, in this kind of solar energy system, an additional heating device is needed to provide extra heat to the room and to the absorption type refrigerator. During operation of an absorption type refrigerator, excess heat is typically discharged to the outside of the building. To meet this requirement, a specially designed fan, coil unit, and cooling tower are attached to the refrigerator unit. Heat energy from the heat condensing tank or the additional heating device is used directly for either heating through use of a heater or for cooling through use of an absorption type refrigerator. The average energy efficiency rate of an active solar energy system used for heating, cooling, and bathing is in the range of about 40%. In circumstances where an active solar energy system is used only for heating and bathing, the efficiency rate will be about 25%. Significant problems with conventional heating and cooling systems include corrosion, including rust, the need for complicated piping, a special control unit, and a complicated structure to support a solar energy collection plate.

[0004] A conventional solar energy collecting plate is often equipped with a copper pipe incorporating a wick. In conventional systems, heat media is repeatedly cycled through evaporation and condensation steps during flow of the media through the pipe. Heat exchange occurs through this cycling and the heat media (such as for example, a thermally conductive fluid) returns to its original phase and location through a wick after completion of the heat exchange step. In a conventional heat exchange structure, heat exchange only takes place within a limited area determined by the physical characteristics of the conventional system. A conventional system often requires a complicated structure for the solar collection plate and heat exchanger components that must be attached to other conventional system components.

[0005] In view of the various limitations presented by conventional heat exchange systems and apparatuses, a more simplified heat exchanger structure is desirable. In the present invention, a simplified heat exchanger structure is provided. In addition, a simplified solar energy collecting plate is also provided. In one aspect, the invention provides a solar energy collecting plate in which heat exchange occurs directly within the solar energy collecting plate without use of an additional heat exchanger system.

[0006] In another aspect of the invention, an improved solar energy collector is provided in which heat absorption and heat exchange functions are facilitated in substantially the same place and time. Substantial amounts of solar energy are absorbed from outside of the system and are directly transferred to a heat pipe that is in turn embedded inside of a water pipe. In another aspect, the invention includes an improved heat exchanger incorporating an improved heat pipe. The heat exchanger and solar energy heater may be used to collect solar energy from outside of the structure and to facilitate heat transfer to water circulating within, or fed by a water pipe.

[0007] In another aspect of the invention, an improved floor heating system may be provided. By way of example, the improved floor heating system may substantially shorten the length of water pipe required to effectively heat a floor or other interior surface. The water pipe forms a water jacket in which the heat pipe is installed to allow heat transfer from hot water received from outside of the heat receiving area. The installed heat pipe is provided as part of an efficient heat exchanger system to cycle fluid within the target heat distribution area.

[0008] In a further aspect of this invention, a supplemental heater may be added to provide additional heating sources to a building or other structure The additional heating apparatus may be powdered by a magnetic generator. The magnetic generator may also provide supplemental power for heating up water flowing in thermal communication with the solar energy collecting plate. This invention also includes a planar heat pipe heater that may be used in association with a solar energy collector and heating apparatus.

SUMMARY OF THE INVENTION

[0009] In one aspect of the invention, a heat exchanger apparatus is provided. The heat exchanger defines an exterior surface provided for receiving solar energy. On the first side of this surface, a first area is used as a heat acceptor and transfer element. The exterior surface is operatively associated with a second area which is in thermal communication with flowing water. Solar energy is collected by heating the solar energy collector plate in the first area. Heat exchange takes place with the water flowing across the second area defined by a surface of a heat pipe. The heating of the first area and the heat exchange within the second area takes place at substantially the same time and place. The heat pipe may be installed inside of the solar energy collection plate to allow the heat pipe to contact the external energy source, such as for example, a hot temperature generated through absorption of solar energy Water is circulated in thermal communication with the heat pipe. Water is circulated by a water pump to facilitate heat exchange at the second area The water pipe or pipes used in association with the heat exchanger also define an inlet and an outlet for a closed circulation system of the heat pipe.

[0010] In another aspect, the heating apparatus for use in a solar collector includes a heat exchanger as described above. The apparatus further includes a solar energy collector, a hot water reservoir, which receives water heated by the solar energy collector and heat exchanger components, an additional heating device to provide supplemental heat energy to the water within the hot water reservoir if desired, a control unit to control operation of the apparatus, and a heater to distribute heat energy within a target heating area. The solar energy collector plate may be provided with water pipes and an electricity generating module located inside of the solar energy collector plate. Heated water is discharged from the collector plate and is transported for storage in a hot water reservoir. An additional heating device may be provided to provide a supplemental heat source to heat the water within the water reservoir to a desired temperature. The additional heating device may be supplied with electric power obtained from a generator. Hot water pipes are connected to the hot water reservoir to in turn provide and control the necessary amount of heat to be delivered to a heater positioned within a building or other structure.

[0011] In another aspect of the invention, the heater comprises the heat exchanger of the present invention. The heat pipe component of the heat exchanger will be installed to thermally communicate with the target heated area. The heat pipe is in thermal communication with the interior of a water jacket defined by a hot water pipe supplying hot water from the reservoir.

[0012] In a preferred embodiment, the solar energy collector includes a structure comprising the first area that is in thermal communication with one side of the solar collector plate to receive heat energy from the solar collector plate. Heat collected in this manner flows through the second area. The second area is located inside of the water pipe. This structural arrangement facilities heat exchange with flowing water during operation of the system.

[0013] A battery may be added to a generator to provide an electrical power source for extended times of operation. A thermoelectric module may be used in connection with such an additional power source for supplementing heating of the water in the hot water reservoir

[0014] Further details and an explanation of the various aspects of the invention will become apparent upon review of the attached drawings which are appended to this application.

IN THE DRAWINGS

[0015]FIG. 1 is a schematic representation of a solar collector and heat exchange apparatus.

[0016]FIG. 2 is a cross sectional view, in schematic, of a solar collector and heat exchange apparatus as shown in FIG. 1.

[0017]FIG. 3 is a schematic representation of a heating apparatus for use in an embodiment featuring a solar energy collector apparatus.

[0018]FIG. 4 is a schematic representation of a portion of a piping layout for use in a household heating system using a heating apparatus powered by a solar energy collector.

[0019]FIG. 5 is an exploded, perspective view of a preferred embodiment of a heat pipe assembly of the invention.

[0020]FIG. 6 is an enlarged, partial sectional view of two heat pipes positioned within a preferred planar heat pipe array shown in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0021] With reference to FIGS. 1 and 2, a heat exchanger 100 comprises a water pipe 110 having a water inlet 111 and water outlet 113. Water flows within the water pipe 110, entering at water inlet 111 and exiting the water pipe at water outlet 113. The heat exchanger includes a second area 124 located inside of the water pipe 110. A first area 122 is defined by the heat pipe 120. The first area 122 is located outside of the water pipe 110. Water pipe 110 accommodates or houses a portion of heat pipe 120 (i.e. the first area) by forming a water jacket enclosing a portion of the heat pipe 120. Access ports 112 and 114 of heat pipe 120 define that portion of heat pipe 120 which allows thermally conductive fluid to flow through the water jacket. Access port 114 of the heat pipe 120 represents an opening for thermally conductive fluid flowing within that portion of the heat pipe 120 which is positioned within the water jacket defined by the water pipe 110. The thermally conductive fluid charged within the heat pipe 120 circulates within a closed fluid circulation system separated from the hot water circulation system The heat exchanger 100 facilities the exchange of heat energy collected through the solar energy collector 130 and transferred to the heated water flowing through water pipe 110.

[0022] The solar energy collector 130 is preferred for use in connection with heat exchanger 100. In the preferred embodiment, in which the heat exchanger 100 is powered by solar energy, the first area 122 of heat pipe 120 is installed below solar collector plate 130 to facilitate effective thermal communication with the plate. In the preferred embodiment, the second area 124 is installed within the water jacket of water pipe 110 to effectively heat the water supplied by the water pump 110.

[0023] Cooling pipe 140 may be provided in an embodiment featuring a pre-selected number of thermoelectric modules 410. Cooling pipe 140 provides a water cooling stream in thermal communication with the cooling faces of thermoelectric modules 410 which modules are used to generate electrical power. Insulation material 150 is installed on the exterior of the cooling pipe, on the side opposite the thermoelectric modules.

[0024] With reference to FIGS. 3 and 4, a heating apparatus is described for use in connection with a solar energy collector system. Heating apparatus 600 includes a heat exchanger 100, a hot water reservoir 200, a heater 300, electricity generating module 410, battery 420, thermoelectrical module 430, and a generating unit.

[0025] Thermal electrical module 430 is placed at the base of the hot water reservoir 200. Heater 300 is thermally connected to the hot water reservoir. Hot water flows and circulates through a hot water pipe 330, under controlled conditions maintained by a control unit.

[0026] A target heated area generally corresponds to the area occupied by heater 300. In the heater 300, the first area 310 of the heat pipe is embedded in a floor or other structural surface outside of the hot water pipe 330. The second area 320 of the heat pipe is installed inside of a water jacket defined by hot water pipe 330. The first area 310 of the heat pipe and the second area 320 of the heat pipe form a closed loop for circulating thermally conductive fluid. The thermally conductive fluid circulates within the inner chamber of the heat pipe. Adapter 340 is provided as a connector for fluid flowing through the water jacket defined by hot water pipe 330. By way of example, adapter 340 may be used to adapt smaller diameter piping used to accommodate hot water flow through the water jacket defined by the hot water pipe 330.

[0027] In this embodiment, the heat pipe is used to exchange heat supplied from a circulating water source rather than directly from a solar collector plate as previously described in the subject application. In the present embodiment, the heat pipe is thermally associated with a heat source defined by a hot water stream circulating within a hot water pipe. The heat pipe array effectively distributes heat supplied by hot water pipe 330 to the target area.

[0028] In an embodiment of the heat exchanger 100 that was tested, it was found that it was possible to increase the operating temperature of the system from about 78° C. (provided by using a conventional heat exchanger arrangement) to an operating temperature in the range of about 95° C. to 100° C. obtained by using a system having a heat pipe of the present invention. In the tested embodiment of the invention, the heat exchanger 100 was provided with a first area 122 on a capillary-type heat pipe installed within heat exchanger 100. It was noted that the operating temperature of the heat pipe 122 heated up rapidly as energy was transferred from the solar collector plate and relayed to the inside water pipe 110 via the thermally conductive fluid media charged within the heat pipe. The water circulating within the water pipe 110 was rapidly heated to a higher operating temperature when compared with the conventional heat exchange apparatus.

[0029] The simplified heat exchange structure that was tested incorporated a heat pipe defining a plurality of 4 mm diameter capillary tubes circulating within a closed loop system defined by a heat exchange manifold of the present invention. The heat exchange manifold defined an interior chamber charged with a thermally conductive fluid. The thermally conductive fluid was charged to circulate within the closed loop system defined by the heat exchange manifold. The first portion of the interior chamber of the manifold was occupied by a liquid phase of the thermally conductive fluid. The second portion of the interior chamber defined by the heat exchange manifold was occupied by a vapor phase of the thermally conductive fluid. A solar collection apparatus comprising the heat exchange manifold described herein was found to effectively increase the operating temperature of the heat pipe to a range of 95° C. to 100° C. The added energy recovered by the heat pipe will in many instances lead to added energy efficiency where the water within the water pipe 110 may be heated to higher temperatures. At the same time, certain applications will permit embodiments of this invention to generate electrical power by harnessing the additional heat recovered from the solar collector plate. By way of example, additional electrical power may be generated by incorporating electricity generating modules that may be used to maintain or elevate the temperature of water stored within the water reservoir.

[0030] The present invention may also be used in association with energy sources other than solar powered energy sources. By way of example, the heater 300 is an example of a water-sourced heat supply applied to the first area of the heat pipe. An alternate heat source may be used to transport the energy to the second area of the heat exchange apparatus. The basic heat pipe structure and heat exchange manifold of the present invention may be applied to other heat exchange systems.

[0031] In FIGS. 3 and 4, a heating apparatus of the present invention includes a heat exchanger of the present invention. The heating apparatus is provided with a water pipe that supplies hot water to a hot water reservoir and a second water pipe used to supply hot water to a heater. A thermoelectric module 430 may be installed to maintain the temperature of the hot water stored within the hot water reservoir. The power supply for this thermoelectric module 430 may be provided by an electricity generating module which is installed inside of the solar electric plate 100 or from the battery unit 420. The battery unit 420 may supply the necessary power to the thermal electric module at any time, including evenings and during inclement weather. The hot water is stored within the hot water reservoir within a desired temperature range and in sufficient volume to furnish significant quantities of hot water for heating purposes. The hot water supplied to heater 300 circulates through hot water pipe 330. Hot water pipe 330 is installed in a linear arrangement defining a hot water jacket to facilitate heat exchange with the second area 320 of the heat pipe. The first area 310 of the heat pipe is typically installed beneath the surface of the floor targeted for heating. Typically, heating of the floor surface will be sufficient to maintain the temperature of the corresponding rooms at a desired level. The piping used for this heating function includes, the piping within the heat exchanger 100, the hot water pipe and heat pipe within the heated area where the heat exchange takes place. The heating apparatus of the present invention may include a planar heat pipe described above for installation within a solar collecting plate. Embodiments of the invention may be used for supplying hot water, and heating and cooling.

[0032] In applications featuring floor heating components, the heat pipe is placed below the surface of the floor as a replacement for a hot water network of tubing that would otherwise circulate hot water. The total length of hot water piping is significantly reduced by employing a heat pipe distribution network. In many instances, the use of the heat pipe network reduces the risks of leakage and rust related problems arising within a larger network of hot water piping. For example, a suitable, stable and non-corrosive thermally conductive fluid may be circulated within the heat pipe network. Furthermore, in embodiments of the invention in which a heat pipe network is used to replace hot water piping, it is possible in many instances to provide a substantial improvement in energy efficiency.

[0033] The electricity generating modules installed inside of the solar collector plate generate power during solar energy collection. This energy may be used to either raise or maintain the temperature of the hot water stored within the hot water reservoir in a highly efficient manner.

[0034] With reference to figures FIGS. 5 and 6, a preferred embodiment of the invention features a coplanar array of heat pipes 220. The coplanar arrangement of heat pipes 220 is secured in fluid communication with tail pipe 230 and head pipe 210. In this embodiment, the tail pipe of the heat exchanger is enclosed within an annular jacket of a pipe 230. Pipe 230 is provided with a fluid inlet and fluid outlet, to allow fluid movement along the longitudinal axis of the jacket pipe 230. Water is pumped into the fluid inlet, into the annular jacket of jacket pipe 230, and the water exits through the fluid outlet. Water passing through the annular jacket of jacket pipe 230 will be heated upon thermal communication with the portions of the heat pipes which extend into an interior chamber of the jacket pipe 230. The thermally conductive fluid within the heat exchanger is not in fluid communication with the water circulating through the annular jacket of the jacket pipe 230.

[0035] A number of horizontal banks of thermoelectric modules are secured in close contact with the coplanar array of heat pipes 230. In this particular application, the thermoelectric modules are the electric generating modules positioned to absorb heat from the thermally conductive fluid circulating within the heat pipes. In this particular heat exchanger system, the heating faces (not shown) of the electricity generating modules 240 are all preferably positioned so that they absorb heat from the thermally conductive fluid contained within the heat pipes, to induce generation of electricity by the associated modules. A second water stream may be pumped through cooling jackets 299. It will be understood that, the heating faces of the electricity generating modules will be positioned for thermal communication with the heat pipes 220, and the cooling faces of the modules will be in thermal communication with the cooling jackets 299.

[0036] With reference to FIG. 6, two adjacent heat pipes are shown in a coplanar arrangement. Each heat pipe defines a plurality of distinct capillary channels which extend along the entire length of each heat pipe. Each heat pipe 220 is flat, elongated and forms an essentially hollow planar structure. Each heat pipe 220 has an elongated front wall and an opposing elongated rear wall. The two opposing elongated walls provide substantial surface areas for heat transfer functions. The interior of each pipe 220 is divided by interior walls which define elongated capillary channels. The capillary channels extend along the length of each heat pipe. The capillary channels open at opposing top and bottom ends of the heat pipe. The upper ends of the heat pipes shown in FIGS. 5 and 6 open into the interior of the head pipe 210. The lower ends of the heat pipes 220 open into a tail pipe portion positioned within the interior of the hot water jacket 230. The head pipe 210, heat pipes 220 and the tail pipe (not shown) define a closed system for circulation of a thermally conductive fluid. The thermally conductive fluid circulating within those three components (the head pipe 210, heat pipes 220, and the tail pipe) is not in fluid communication with the hot water passing through the hot water jacket 230. However, the thermally conductive fluid within the heat pipes is in thermal communication with the hot water passing through the hot water jacket 230.

[0037] When the heat pipes 220, head pipe 210, and the tail pipe are fully assembled, they form a fully enclosed system for circulating the thermally conductive fluid. During assembly, an access port (not shown) may be used to evacuate entrapped air from within the internal chambers of the tail pipe, head pipe and capillaries within the heat pipes. In a preferred embodiment, the interior chamber of the heat pipes is drained of entrapped air so that a substantial vacuum is created. Thereafter, the interior chamber of the tail pipe, head pipe and capillaries of the heat pipes are filled with an effective amount of the thermally conductive fluid until a substantial portion of the interior volume of that structure is filled with a liquid phase of the thermally conductive fluid. The remaining portion of the interior volume is filled with the vapor phase of the selected thermally conductive fluid. After the manifold is charged with the appropriate fluid, the access port may be closed by applying a suitable stopper or cap (not shown).

[0038] In a preferred embodiment, the fluid within the interior volume is filled until the liquid phase occupies about 40% to 70% of that interior volume. The vapor phase will occupy between about 30% and 60% of that interior volume, in a preferred embodiment.

[0039] In a further preferred embodiment of the invention, the capillary channels in a heat pipe are generally rectangular tubes defined by the interior walls of each heat pipe. Preferably, the interior walls extend orthogonally from one face of the heat pipe to the opposing face of the heat pipe. However, the capillaries may be manufactured to have other cross-sectional configurations that are not necessarily square or rectangular in shape. The relative size of the capillaries may vary according to the design requirements and characteristics of the desired heat exchange system. In a preferred system directed to the use of water based thermally conductive fluid systems, the diameter of the capillaries will typically range below about 4 mm. In some instances, it may be desirable to provide additives or other fluids to enhance the physical properties of the fluid circulating within the capillaries. Consequently, the diameter of the capillaries may be adjusted to accommodate the particular characteristics of a specific fluid selected for use in the system.

[0040] In the preferred embodiment shown in FIGS. 5 and 6, the capillaries are arranged in a single layer of capillaries within the outer walls of the heat pipes 220. In other instances, multiple layers of capillaries may be provided within the outer walls of the heat pipe, although in many cases, such an arrangement may not be preferred.

[0041] In other instances, the heat pipe array shown in FIGS. 5 and 6 may be used in association with other similar heat pipe arrays arranged into banks of parallel arrays. The heat pipes, head pipe, and tail pipe are preferably made of relatively strong, resilient, and thermally conductive material and most preferably, a metal which is not susceptible to excessive corrosion. Aluminum is a particularly useful material of construction for many applications of the present invention. Of course, persons skilled in the art will understand that other materials, including other metals, alloys, or non metallic materials may be desirable for use in the particular conditions and circumstances under consideration

[0042] A variety of thermally conductive fluids may be used according to the design requirements of a particular system For example, in heating applications, many conventional fluids including water, acetone, ethanol and methanol may be desirable as relatively low-cost thermally conductive fluid choices for use within the heat pipe system. It will be appreciated that the foregoing examples of potentially useful fluids are merely illustrative and are not intended to represent an exhaustive list of all suitable thermally conductive fluids

[0043] In some heat exchange systems, capillaries having cross-sectional diameters of about 4 mm in diameter will be particularly efficient in heat transfer applications. In another instances, it may be desirable to use capillaries with smaller effective diameters. Capillaries that are generally rectangular when viewed in cross-section may have dimensions of 1 mm×1.4 mm or lower. In other instances, the capillaries may have cross-sectional dimensions of about 0.5 mm×0.6 mm. Of course, other sizes of capillaries may be selected based on various design considerations.

[0044] It will be appreciated that thermally conductive fluids will tend to flow within the internal channel of the heat pipes due in part to the heating or cooling of the fluid within the heat pipes and the capillary action exerted on the fluid within the capillaries of the heat pipes. One of the advantages of the invention is that it is unnecessary to provide a circulating pump to circulate the thermally conductive fluid within the interior chamber of the heat pipes. Although there may be instances where a circulating pump may be added for that purpose, such a pump would not be necessary to circulate the thermally conductive fluid filled within the interior volume of the head pipe, heat pipes and tail pipe.

[0045] It will be appreciated that the present invention has been described with reference to preferred embodiments and other examples. However, other embodiments of the invention, variations and modifications of those embodiments will be apparent to those persons having ordinary skill in the art. It is intended that those other embodiments, variations and modifications thereof, will be included within the scope of the present invention as claimed within the appended claims. 

We claim:
 1. A heat exchanger comprising: a solar energy collecting unit providing a first thermal transfer area defined by a solar energy receiving plate; a second thermal transfer area for thermal communication with a heat pipe; the heat pipe is positioned within the solar energy collecting plate; one surface of the heat pipe is in thermal communication with the solar energy collecting plate; and a second surface of the heat pipe is in thermal communication with a fluid stream.
 2. The heat exchanger of claim 1 comprising: a water pipe defining a water jacket for housing a contained portion of the heat pipe; and a thermally conductive fluid flowing within the heat pipe is not in fluid communication with water flowing within the water pipe.
 3. In the heat exchanger claimed in claim 2, the contained portion of the heat pipe defining the second thermal transfer area.
 4. In the heat exchanger claimed in claim 3, a portion of the heat pipe, other than the contained portion, defining the first thermal transfer area.
 5. In the heat exchanger claimed in claim 4, the heat pipe defining a plurality of parallel capillary channels extending along the length of the heat pipe, for circulation of the thermally conductive fluid within a closed loop.
 6. The heat exchanger claimed in claim 4 comprising: an effective amount of the thermally conductive fluid, of which a liquid phase occupies a first portion of an interior volume defined by the heat pipe, and a liquid phase occupies a second portion of the interior volume.
 7. A heating apparatus comprising: a solar energy collector comprising a first heat exchanger; a power supply comprising an electricity generating module operatively connected to the solar energy collector; a hot water reservoir for storing hot water generated by the first heat exchanger, a thermoelectric module powered by the power supply, the thermoelectric module being operatively connected to heat the contents of the hot water reservoir to a first predetermined temperature; a heater comprising a second heat exchanger in thermal communication with hot water supplied from the hot water reservoir; and a control unit to maintain the operating temperature of the heater at a second predetermined temperature
 8. The heating apparatus claimed in claim 7, wherein the solar collector comprises a first thermal transfer area in thermal communication with a thermal energy collector plate; a second thermal transfer area contained within a water jacket, the water jacket defining a water inlet and defining an outlet for hot water supplied from the first heat exchanger.
 9. The heating apparatus claimed in claim 8, wherein the first thermal transfer area is in thermal communication with the second thermal transfer area.
 10. The heating apparatus claimed in claim 9, wherein water flowing into the water jacket is in thermal communication with the second thermal transfer area.
 11. The heating apparatus claimed in claim 10, wherein the second heat exchanger comprises third and fourth thermal transfer areas; the third thermal transfer area provided for thermal communication with an interior surface of a building structure; and the fourth thermal transfer area located within a pipe supplied with hot water from the hot water reservoir.
 12. The heating apparatus of claim 11 wherein the power supply comprises an electrical storage battery operatively connected to the thermoelectric module
 13. The heating apparatus of claim 8, wherein the first heat exchanger comprises a heat pipe defining a plurality of capillary channels for containing a thermally conductive fluid; and the heat pipe defining the first and second thermal transfer areas.
 14. The heating apparatus of claim 13 wherein the heat pipe defines an interior volume for storing a first liquid portion of the thermally conductive fluid and a second vapor portion of the thermally conductive fluid.
 15. The heating apparatus of claim 14 wherein the first thermal transfer area is defined by an exterior surface of the heat pipe and the second thermal transfer area is defined by a second exterior surface of the heat pipe.
 16. The heating apparatus of claim 15 wherein the heat pipe is positioned in a coplanar array defined by a plurality of like heat pipes.
 17. The heating apparatus of claim 15 wherein the first liquid portion occupies between about 30 percent and 60 percent of the interior volume, and the second vapor portion occupies between about 40 percent and 70 percent of the interior volume.
 18. The heating apparatus of claim 17 in which the capillaries have a diameter of less than about 4 mm.
 19. The heating apparatus of claim 18 in which the capillaries have a diameter less than about 1.5 mm.
 20. A heat exchanger, for use in a solar energy collecting unit, comprising: a manifold comprising a first cylinder parallel to a second cylinder, and a plurality of elongated, planar heat pipes defining capillaries in fluid communication between interior spaces defined by the first and second cylinders; the manifold defining a solar energy collecting surface and a first heat transfer area; and a fluid jacket defining a fluid inlet and fluid outlet for a stream in thermal communication with the first heat transfer area.
 21. The heat exchanger claimed in claim 20, wherein the manifold defines a second heat transfer area for communication with a power generating array of thermoelectric modules.
 22. The heat exchanger claimed in claim 21, wherein the heat pipes are co-planar, defining a first flat wall comprising the solar energy collecting surface.
 23. The heat exchanger claimed in claim 22, where the heat pipes define a second flat wall, defining the second heat transfer area.
 24. The heat exchanger claimed in claim 23, comprising a pre-selected number of pipes in cooling, thermal communication with the thermoelectric modules.
 25. The heat exchanger claimed in claim 20, wherein the heat pipes define a vertical plane when in operation. 